Apparatus for centrifugally molding concrete pipes and other tubular bodies



Aug. 21, 1934. R. WILLIAMS APPARATUS ROR CENTRIFUGALLY MOLDING CONCRETEPIPES AND OTHER TUBULAR BODIES Filed July 27, 1952 Patented Aug. 21,1934 Unire 'stares' tries 'APPARATUS FORA CENTRIFUGALLY MOLD- ENGCNCRETE PIPES AND OTHER TUBU- LAR BDHES Ralph Williams, Sydney, NewSouth Wales,

Australia Application July 27, 1932, Serial No. 625,071 lin AustraliaSeptember 17, 1931 2 claims. (oies-.30)

This invention relates to improved centrifugal molding apparatus for themanufacture oi concrete pipes. and other tubular bodies in which moldscontaining concrete or like plastic cern action is applied to theconcreteV or other material` in the molds so that the pipes or otherarticles produced are particularly dense in character and are :free fromair bubbles and voids or cavities. f

Another object of the invention is to provide centrifugal moldingapparatus in which generally the manufacture of concrete pipes may bemore expeditiously effected, and in which special detachable molds arecharged with cemn entitious material before they are inserted into arotatable carrier to mold the contained mam terial into the requiredform. A

A further object resides in the provision of centrifugal moldingapparatus in which the `mold carrier is mounted on adjustableantifriction bearing rollers and is adapted'to receive interchangeableholders for detachable molds of diierent sizes, and in which a' brake isprovided to quickly arrest the rotation of the mold. carrier whenrequired.

The invention also provides an improved pipe mold adapted to be Yreadilyplaced in and driven by the rotatable mold carrier and provided with adetachable former shaped to correspond with the interior oi a pipefaucet.

In the accompanying explanatory drawlngi- Fig. 1 is a side elevation ofcentrifugal molding apparatus according to Vthe invention.

Fig. 2 is an end elevation of the molding apparatus.

Fig. 3 is a transverse section of the molding apparatus.

Fig. 4 is a sectional View of a detail.

Fig. 5 is a transverse section of4 the antifriction bearing roller seenin Fig. fi.'

Fig. 6 isa view partly in elevation and partly insection of a pipe mold.

Fig. '7 is a section of portion of a modiiied pipe mold. p

In the drawing, 1 indicates a base or bed plate upon which are iXedaxially aligned hollowbearing housings 2. These bearing housings arepreferably made in two parts, the lower part 3 being bolted to the baseor bed plate 1, and the upper part 4 being detachably secured to thelower part 3 by bolts rllhe bolts 5 are passed through franges c and 7ormed respectively on the upper and lower parts of the housings 2, andremovableshims or liners 3 may be inserted between the flanges 6 and iso that the parts 3 and Il of the housings may be brought more orlessclosely together.

The bearing housings 2 are of trough-shape or section-see Fig. 4-andmounted on spindles or bolts 9 extending `transversely through thehousings 2 are vanti-friction rollers 10 fitted with' ball bearings asshown, or with roller bearings or other type of suitable antiefrictionbearings.

The ball bearing rollers l0 are evenly spaced at equal radial distancesfrom the axis oi the bearing housings 2 and their inner races 11 areeccentricaliy mounted upon the spindles or bolts 9 and are non-turnablyfixed to the same as by keys i2; see Fig. 5. Accordingly, it will beobserved thatby turning theY spindles or bolts 9v the rollers 10 can beadjusted towards or away from the axis of the housings 2 forV a purposehereinafter referred to. The anti-friction rollers 1G Vare maintained ina central position in theV bearing housings 2 by collars 13 mounted uponthespindles or bolts 9.

The outer races 14 of the ball bearing rollers lo are encircled withannular hardened wearing bands 15 which iit and roll inv peripheralgrooves 16 in annular bearing rings 17. These annular bearing rings ritireelyvin the bearing housings 2 and are disposed peripherally about andfixed to` a tubular mold carrier 18.

`1n Figs. 2 and 3, three anti-friction rollers 10` are shown, the samebeing evenly disposed about the mold Vcarrier 18, butv a greater numberof said rollers may be used if required. However, it will be understoodthat if less than three anti'- iriction rollers 10 are employed it willnot be possible to avoid slackness oi the rotatable mold carrier 1S orto spin the same at high speed.v

The interior oi the Vmold carrier 18 is provided with mold supports orholders 19 which are bored at 20 to accommodate and accurately centre a.mold 21, see Fig. 3. The supports or holders 19 maybe convenientlyformed as east ings, and they may be detachable andy nter# changeable-with othersof various sizes, so that molds of greater or lessdimensions may beI readily accommodated'in the mold carrier 18.A

` The mold 21 (shown separately in Figs. 6 and 7) is preferably made intwo semi-cylindrical portions or halves 22 and 23 havingangle strips 24Xed along their edges. The two halves or semi-cylindrical'portions 22and 23 are'secured together to formthe mold 21 by bolts 25 passingthrough the adjoining angle strips 24.

In order to permit the mold 21 to be inserted into the mold carrier 18and to provide a driving connection between the latter and the former,

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the holders or castings 19 are provided With opposed radial slots 26.These radial slots accommodate the angle strips 24, and the edges ofsaid slots by contact with the angle strips provide a positive drivingconnection between the mold carrier 18 and the mold 21 and preventindependent rotation of the latter and the former.

The mold 21 at one end may be provided'with an angle ring or internalnan-ge 2'7 forming a circular opening 28 of somewhat less diameter thanthe interior of the mold 21.

The opposite end of the mold 21 may be provided with an enlargement 29shaped to correspond with the external contour of a pipe faucet.Detachably tting the exterior of the enlargement 29 is an annular memberor former 30 shaped to form the interior of the pipe faucet.

The annular member 30 may be secured to the enlargement 29 by a bayonetVslot 31 made in the former and adapted for engagement with a projectingpin 32 xed in the latter. Alternatively, the detachable annular former30 may be xed to the enlargement 29 by wing nuts 33 or other suitablefastenings.

In practice, the two halves 22 and 23 oi the mold 2l are oiled andassembled by the bolts 25, and the mold is then placed on end with thefaucet enlargement 29 downwards, the annular former 30 being suitablyplugged. Suiiicient concrete or other cementitious material to form apipe of required thickness is then placed in the mold 21 and the opening28 is suitably plugged. The charged mold 21 is then placed in positionin the mold carrier 18, and the latter is set in rotation, preferably bya driving belt 34 applied to its periphery.

The mold carrier 18 with the mold 21 therein is then slowly rotated fora short period to enable the concrete to become evenly distributed overthe inner surface of the mold. The speed is then increased and the mold21 is rotated for a suflicient time at nigh speed to consolidate theconcrete material.

Trowelling means of well-known construction is quickly run over theinterior of the pipe during the formation to withdraw the water andslurry separated by the compacting centrifugal action and to render thesurface of the finished pipe hard and smooth.

A brake is provided toy enable the rapidly rotating mold carrier 18,mold 21 and the pipe therein to be quickly brought to rest, whenrequired. The brake may be oi anyk suitable construction and hand orfoot operated, and it may comprise a post 35 Xed to the base 1 and prouvided with a lever 36 and brake shoe 37 to be applied to the peripheryof the mold carrier 18 by manual operation.

The interior of the bearing housings 2 may be subdivided into chambers38 by transverse partitions 39 positioned `adjacently to and on oppositesides of the anti-friction rollers 10. The said chambers 38 may bepacked with suitable semi-iluid lubricant and, theyrmay be provided withlubricatingqdevices e0. Accordingly, the anti-friction rollers 1G andthe annular bearing rings 17 are at all times efficiently lubricated,thereby ensuring silent and smooth operation and minimizing wear. i v

At the conclusion of the spinning operation, the mold carrier 18 isstoppedby the brake shoe 37, and the mold 21Vis removedand set aside,for

a sufficient time to permit the concrete material to properly set andharden. The annular faucet member or former 30 is then removed and thebolts 25 are withdrawn, thereby permitting the semi-cylindrical portions22 and 23 to be taken from the finished pipe.

Owing to the high speed made possible by the anti-friction rollers 10and the eiiicient lubrication, the iinished pipe is very dense, smoothand hard. Moreover, it may be readily removed from the mold 21 withoutsteaming, and generally in about live hours after the termination of thespinning operation, thereby permitting the molds 21 to be used twicedaily.

The adjustable feature of the ball bearing rollers l previouslydescribed enables the mold carrier 18 to be accurately centered in eachof the bearing housings 2, so that it may spin with minimum frictionalresistance and without shake or looseness. Moreover, by adjustment ofthe rollers 10 and removal of one or more of the linersor shims betweenthe lower part 3 and the upper part 4 of the bearing housings 2, wear ofthe rollers 10 and annular rings 17 may be compensated for and correctalignment of the mold carrier 18 and bearing housings 2 may bepermanently maintained.

It will be understood that as the concrete material is placed in themold 21 before the commencement of the spinning operation, theundesirable reduction of the water content brought about when thematerial is thrown in shovelfuls into the rotating mold is obviated.

What 1` do claim is:-

1. A centrifugal molding apparatus including a base, a plurality oftwo-part annular housings carried by the base, one part of each of saidhousings being Xed to the base, the remaining part of each of saidhousings being adjustably connected to the fixed part, ball bearingsupports mounted in the respective parts of each housing, a mold carrierarranged within each housing and rotatably supported on the ball bearingsupports therein, one of said ball bearing supports being ecoentricallymounted for adjustment toward and from the mold carrier, each ballbearing support including an annular member removably mounted on theball bearing support and forming the bearing for direct contact with themold carrier, and an element on the mold carrier disposed in an openinner periphery of each annular housing to provide bearing contact withthe removable member of the ball bearing.

2. A centrifugal molding apparatus including` a base, a rotating moldcarrier, an annular housing encircling the carrier adjacent each endthereof, each housing comprising a part xed to the base and a secondpart adjustably connected to the IiXed part, the parts of the housingbeing formed with chambers opening toward the carrier, a ball bearing ineach of said chambers, means for eccentrically mounting atleast one ofsaid ball bearings to provide for its adjustment toward and from thecarrier, said ball bearings including an annular separable memberformling the contacting element between the bearing and carrier, and anannular member securedto the carrier and formed with a channel toreceive said separable member.

RALPH WILLIAMS.

